The invention relates to the production of capillaries for gel electrophoretic (CGE) separations. In particular, narrow bore fused silica capillaries are filled with a solution of a polymerizable material. The material is polymerized within the capillary by radicals generated by .gamma.-radiation, preferably originated from a .sup.60 Co-source.
Capillary gel electrophoresis as a powerful separation technique especially for the rapid separation of oligonucleotides has been introduced by Karger et al., A. S. Cohen, D. R. Najarian, A. Paulus, A. Guttman, J. A. Smith, B. L. Karger, Proc. Natl. Acad, Sci, USA 85 (1988) 9660, EP-A 0 324 539 and U.S. Pat. No. 4,865,706.
Conventionally gel filled capillaries are produced by a method using radical initiators, such as ammonium persulfate and TEMED (N,N,N',N'-tetramethyleneethylene diamine), as stabilizing agent. Such capillaries may possibly contain highly charged by-products and residual amine which should be removed before use or storage.